CVE-2025-40216

In the Linux kernel, the following vulnerability has been resolved:

io_uring/rsrc: don't rely on user vaddr alignment

There is no guaranteed alignment for user pointers, however the calculation of an offset of the first page into a folio after coalescing uses some weird bit mask logic, get rid of it.

This vulnerability is rated as Moderate severity because exploitation requires local access and specific memory alignment conditions during io_uring registered buffer operations, increasing attack complexity. An unprivileged local attacker could potentially exploit the flawed folio offset calculation to cause memory corruption, leading to a kernel crash and denial of service. Default installations of Red Hat Enterprise Linux 8 are unaffected as the vulnerable folio management code is not present.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.